The present invention relates to a thermal development apparatus by which the thermal developing photosensitive material is heated and developed.
The thermal development apparatus is an apparatus, for example, which is provided with a heating section having a heating member such as a heat roller whose temperature is controlled, a forcing member such as a forcing roller located opposite to the heating member, and a conveying section to convey the heated thermal developing photosensitive material, and by which, when, while an exposure-processed thermal developing photosensitive material is being forced onto the surface of the heating member by the forcing member, the material is closely adhered onto it, the thermal developing photosensitive material is heated and thermally developed.
In such a thermal development apparatus, when the thermal developing photosensitive material is continuously thermal developed, the temperature change of the thermal developing apparatus in a thermal development processing section is generated like the temperature lowering of the forcing member due to the case where the heat is taken by the thermal developing photosensitive material, or the temperature rise of a conveying section due to the heat supply from the heated thermal developing photosensitive material.
Due to the influence of such a temperature change in the thermal development processing section, the processing temperature difference is generated for each continuously processed thermal developing photosensitive material, and as a result, a predetermined density characteristic is not obtained in the thermal developing photosensitive material after the development, and the development density difference is generated.
As the countermeasure for this, there is a thermal development apparatus in which a feedback mechanism of the development density adjustment by conducting the adjustment of the exposure amount in the exposure processing section to form a latent image or the adjustment of the heating amount in the thermal development processing section, based on the measured density value in which the density of the thermal developing photosensitive material after the development is measured, or based on the detected temperature in which the temperature of the member of the thermal development processing section or the ambient temperature in the thermal development processing section is detected, is provided and the development of the predetermined density is conducted.
However, because such a feedback control is delayed in the time and the control is conducted, particularly in the case where the thermal developing photosensitive material is continuously processed, because, to the rapid temperature change of the thermal development processing section, the control does not follow the thermal developing photosensitive material which is thermal developed at the time point, there is a problem that the influence of the temperature difference of the thermal development processing section is subjected for each continuously processed thermal developing photosensitive material, and as a result, in the thermal developing photosensitive material after the development, the predetermined density characteristic is not obtained and the development density difference is generated. Further, in the thermal development apparatus provided with the feedback mechanism of the development density adjustment according to such a measured density or detected temperature, because the apparatus component members become many, there is also a problem that the cost is increased, and the apparatus itself is complicated.